SQLite testing procedures

[bearophile]

Robert Clipsham Wrote:

> This is a fairly old document now, but it has some interesting ideas 
> that could have a place in D (either the language, tools, or phobos):

There is a part about integer overflow checks:

>8.6 Signed-Integer Overflow Checks

The various C language standards say that the signed-integer overflow behavior is undefined. In other words, when you add a value to a signed integer such that the result is too large to fit in that integer, the value does not necessarily wrap around to a negative number, as most programmers expect. It might do that. But it might do something completely different. See, for example, here and here. Even the same compiler might do something different with signed integer overflow in different places in the code or at different optimizations settings.

SQLite never overflows a signed integer. To verify this, the test suites are run at least once when compiled with the -ftrapv option to GCC. The -ftrapv option causes GCC to generate code that will panic() on a signed integer overflow. In addition, there are many test cases the strive to provoke integer overflows using boundary value calculations such as "SELECT -1*(-9223372036854775808);".<

Bye,
bearophile